Earth Observatory Blog

Did you know that in the past six weeks six volcanoes in Indonesia erupted? These volcanoes are Semeru, Anak Krakatau, Merapi, Kerinci, Dukono, and Ibu.

These recent eruptions are part of the usual volcanic bustle in Indonesia, impacting mostly the areas close to the volcanoes. While some of these activities were picked up all the way in Singapore, all were reported to aviation authorities.

Issuing Eruption Notifications

The Centre for Volcanology and Geological Hazards Mitigation (CVGHM), the monitoring agency for Indonesian volcanoes, issued a Volcano Observatory Notification for Aviation (VONA) on each eruption. The notification includes a summary of the volcanic activity, the...

113 years ago, on 4 January 1907, a powerful magnitude (M) 8.2-8.4 earthquake occurred off the west coast of Sumatra, Indonesia. This earthquake belonged to a special class called “tsunami earthquakes” that do not generate very strong shaking, but can result in large tsunamis.

The tsunami that was produced struck Nias and Simeulue, killing thousands. It also struck the distant shores of Sri Lanka, India, and the island of Reunion. The first earthquake was later followed by another quake measuring approximately M 7.0, resulting in the destruction of countless houses.

In the years that followed, the sequence got jumbled and the two events were conflated as one, but the 1907 disaster was preserved in local memory by way of the legend of the Smong – a Devayan word for...

Today is World Tsunami Awareness Day. It is a timely opportunity to create greater global awareness about tsunamis as a geological hazard. Before asking how we can stay safe (or safer) from tsunamis, we must first think about how we might improve on the resilience of our current and future infrastructure.

Let’s start by looking at what a tsunami is. A tsunami is a series of waves caused by an underwater earthquake, a volcanic eruption, a landslide, or meteorological processes (meteo-tsunamis).

So why is SE Asia vulnerable to tsunami hazards? First of all, SE Asia lies in a complex tectonic setting that contains many fault systems and volcanoes. Coupled with a high population density and a tight network of infrastructure in coastal areas, one can imagine just how...

At approximately 9:30pm local time (2:30pm GMT) on the 22nd December 2018, a tsunami struck Indonesia’s Sunda Strait, which lies between the islands of Java and Sumatra, claiming over 430 lives. According to Indonesia’s disaster agency there are at least 1,500 injured, over 120 people still missing, and around 12,000 people have been displaced.

The tsunami occurred during a local holiday for the December solstice, striking a number of popular tourist destinations, including the Tanjung Lesung beach resort in the west of Java. Eyewitness reports indicate there were two separate waves, with the second, larger wave causing the most damage.

The tsunami was caused by a violent eruption of Anak Krakatau (Fig. 1), the "child" of Krakatoa, in the Sunda Strait....

The highly active Sumatran Subduction Zone has produced more than four great earthquakes in the last decade. The first of these was the giant Mw 9.2 Sumatra-Andaman earthquake that ruptured on 26 December 2004. This devastating event was followed by three others – the Mw 8.6 Nias-Simeulue quake in 2005, the Mw 8.4 Bengkulu earthquakes in 2007, and the Mw 7.7 Mentawai tsunami-earthquake in 2010.

In order to understand why so many great earthquakes originate from this region, we have to measure the strength of the rocks in the earth’s lower crust and upper mantle. Our new research, published today on 8 March 2018 in Nature Communications, highlights a ground-breaking new approach to how the strength of these rocks...

In 2004, a devastating tsunami struck coastlines around the Indian Ocean. While studying the long-term recovery of the city of Banda Aceh, Indonesia, we found that reconstruction aid provided mostly near the coast, combined with many people's preferences to move to safer areas instead, has had the unintended consequence of the poor becoming disproportionately exposed to coastal hazards.

Our most recent documentary short film, ‘People of the Forest: Orang Rimba,’ premiered at the Singapore Eco Film Festival in early September 2017. It was a Sunday morning just 30 minutes before the screening was about to begin and only a few people had arrived. Luckily, by show time the room was filled with an enthusiastic audience.

The ‘People of the Forest’ short offers a brief but intimate look at the lives of the Orang Rimba, a minority group of a few thousand nomadic tribespeople who live throughout the forests of Jambi province in Sumatra, Indonesia.

This short is part of a larger project – an upcoming feature film about the complex issues of haze and peatland-burning in Southeast Asia. My crew and I spent several weeks in...

In 2013 and 2015, Singapore suffered from extreme haze. Channel NewsAsia sat down with two experts to find out more about Singapore's haze prospects for 2017.

Assistant Professor Mikinori Kuwata, a Principal Investigator at the Earth Observatory of Singapore, discussed Singapore's haze situation with Vivian Claire Liew, the CEO of the social enterprise PhilanthropyWorks. Asst. Prof Kuwata explained how a combination of factors - both human and natural - will influence the prevalence of haze in Singapore.

Available online from August 14 2017 at 10pm, the video commentary can be viewed here.

Sinabung volcano in Sumatra, Indonesia, has been almost continuously erupting in the last three years. It has been on the highest alert level since 2013.

Most of the eruptions on Mount Sinabung have been small. These eruptions vary between lava flows and dome extrusions that accumulate on the volcanic crater, and include explosions with ash plumes that are lower than 3 kilometres (km) in height.

The most common activity on the volcano are the pyroclastic flows that are generated by the gravitational collapse of the dome rocks that have gathered on the summit. The travel distance of these pyroclastic flows range from 2 km to 5 km. As such, since 2014, the exclusion zones were appropriately implemented up to 7 km of the south (S) sector and 6 km southeast-east (SE-E) of...

Japan is known for its earthquakes and tsunami hazards due to the active collision involving three tectonic plates; the Philippine Sea plate, the Pacific plate and the Eurasian plate. These plate convergences not only created the giant trench system found off the eastern Japanese coastline, they also generated a series of active inland faults close to densely populated cities like Osaka, Nagoya, and Tokyo (Fig. 1).

Active faults found on land are usually shorter in length, and move more slowly than those found under the sea in the giant subduction zone where tectonic plates meet. The earthquakes generated by these inland faults are infrequent, and often smaller in magnitude and intensity than the earthquakes in the offshore subduction zone. However, because these inland...